The water's route
Skimmer or channel and main drain → pump strainer → pump → filter → (heater, salt cell) → return jets. Each part goes in that order in the plant room, as close to the pool as possible.
Sand or glass filter
Most filters are tanks of quartz sand or recycled crushed glass. Water passes from top to bottom and particles stay in the media. Glass filters a little finer and lasts longer. Once a week, or when the pressure rises, you backwash: water runs in reverse and flushes the dirt to drain.
How many hours a day
The aim is for the whole volume to pass through the filter at least once or twice a day in summer. For a family pool that usually means four to six hours, more in a heatwave or with many bathers. A timer in the control panel makes it automatic.
Variable-speed pump
It runs for longer but at low speed, so it uses far less electricity and is almost silent. It speeds up only to backwash or to feed an overflow channel. In a pool that runs all summer, the difference shows on the bill.
